2013-06-02-09.02.33: Moved Replyqueue up from src/lib/src/lib/thread-kit/src/core-thread-kit/internal-threadkit-types.pkg to src/lib/src/lib/thread-kit/src/core-thread-kit/mailop.pkg because it needs access to the ==> op defined in the latter.  Also, demoted drop_from_replyqueue() from a public fn to a private helper for put_in_replyqueue, and added logic in put_in_replyqueue() to wrap given mailop so as to call drop_from_replyqueue() when it fires -- a ridiculously simple solution that occurred to me only yesterday *blush*.